Ink reservoir



K. F. TRIPP INK RESERVOIR April 6, 1965 2 Sheets-Sheet 1 Filed NOV. 8, 1962 K. F. TRIPP INK RESERVOIR April 6, 1965 2 Sheets-Sheet 2 Filed NOV. 8, 1962 1 WT F l m v; B a 1 N a R w w 7: 1 MM/ Z? 17/ //A United States Patent Q 3,17 6,511 INK RESERVOER Kenneth F. Tripp, Peterhorough, N311, assigncr to Markem Machine Company, Keene, N .H., a company of New Hampshire Filed Nov. 8, 1962, Ser. No. 236,381 4 Claims. ((Ii. 101-664) This invention relates to ink reservoirs and more particularly to ink reservoirs of the type employed in decorating and specialty printing art. These reservoirs consist generally of a single steel roll, called a reservoir roll, upon which an ink film is continually deposited from a supply container called a pot. This ink film is subsequently transferred to the printing plate or type face.

In the field of decorating and specialty printing, one

critical area resides in establishing and maintaining on the reservoir roll an ink film which is smooth, continuous, and of desired uniform thickness throughout the printing run.

' The generally practiced prior art method for producing desired films for decorating and specialty printing is t apply liberal quantities of the ink to the roll surface from a pot which is held in close proximity to the steel roll, and then to doctor the ink to a thin film of desired thickness by the use of a scraper or doctor blade preparatory to transferring this ink film directly to the type or printing plate. The doctor blade in most instances generally comprises the bottom edge of the pot, thereby providing means for reducing the ink deposit to a film almost simultaneously with the application thereof.

The prior art has not proved entirely satisfactory, however, since it has failed to provide apparatus which will produce an ink film free of interruptions and surface irregularities on the steel inking rolls. These deficiencies are most generally caused by grit and abrasive contaminants resulting from dried ink particles themselves or foreign matter finding its way into the ink supply.

It is well established in the printing art that the quality of reproduction is, to a substantial extent, determined by the ability to continually maintain and control the smoothness of the ink film during the inking operation.

Many methods for producing smooth ink filmshave been developed. One method, for example, is that employed in the field of flex-ography which utilizes low viscosity inks, thereby permitting the use of a cell metered roll. This is a steel roll having a porous surface comprised of a multiplicity of cells, on the order of from 50 to 200 cells per surface inch of roll. Ink from a supply pot fills these cells and the excess is removed by a doctor blade in the conventional manner heretofore mentioned. The combination of low viscosity ink, celled structure of the roll surface, and the doctor blade running in contact with the roll is intended to reduce the likelihood of surface irregularities occurring in the film thereby improving the smoothness characteristics thereof. This method has met with limited success.

Another method of providing smooth ink films is that of forcing ink of relatively high viscosity to travel over a multiple number of serially placed rolls, compressing it therebetween as it passes from the reservoir to the die or printing plate. This method finds particular application in high speed web-fed presses of the magazine and newspaper printing industry. The inks required in this method have to be extremely slow drying because of their long exposure in their traverse of the plurality of rollers. Vis- (insides of these inks are considerably higher than those used in fiexography printing.

Neither of the latter two methods is particularly adaptable to the present case because the inks employed in decorative and specialty printing must be both rapid drying 3,176,611 Patented Apr. 6, 1965 ice and of relatively high viscosity. Accordingly, the rapid drying requirement precludes the use of multiple rolls and the high viscosity requirement is not compatable with the cell metering concept.

The present state of the art in the field of decorative and specialty printing exhibits certain deficiencies, among which are the presence of surface irregularities in the ink film in the area where the film is presented to the printing element, he. the type, die, or printing plate. These surface irregularities indicate a film of non-uniform thickness and generally appear in the form of circumferential lines in the ink film around the reservoir roll. These lines are in fact film thickness variation and result from either of two sources: (1) a particle of foreign matter lodging on the lip of the doctor blade thereby preventing the flow of ink past the blade at that point; or (2) lines may appear which are thicker than the average film thickness and these are usually the result of a nick in the doctor blade thereby allowing excess ink to pass at that point. Suchfilm irregularities occurring on the reservoir roll during the printing operation are transferred to the type or printing plate thereby rendering an unsatisfactory final print.

The present invention, however, overcomes the aforementioned prior art deficiencies by introducing the concept of forcibly smoothing irregular film deposits by the use of a socalled smoothing bar. By this concept the initially deposited and doctored ink film, with its irregularities, on the steel inking roll is ironed flat by the act of forcing into intimate contact with asmooth, stationary surface, the ink film on the rotating ink roll. This stationary surface or smoothing bar can be of any configuration as long as the contact between the ink roll and surface is truly linear along the axial surface of the roll. A hardened and ground steel rod has been found to do a very acceptable job but other shapes, including fiat plates, would do equally well.

By virtue of the aforementioned smoothing bar concept, there are generated, however, large amounts of frictional heat which act in a detrimental manner in causing the highly volatile-ink film to evaporate very quickly from the steel roll. Accordingly, this invention additionally contemplates a new ink pot configuration whereby the viscous ink mass acts as a heat sink by virtue of self-induced circulation during operation of the device.

Accordingly, it is an object of this invention to provide a method for depositing ink on an ink roller which accurately controls the ink film thickness and uniformity thereof without impairing other operative features.

It is a further object of this invention to provide a means for varying the ink film thickness on the ink roller at will and continually preserve and maintain film continuity at all times.

It is still a further object of this invention to provide an ink pot which will act as a heat sink for the frictionally generated heat resulting from operation of the smoothing bar against the ink roller. Dissipation of this heat reduces the temperature of the ink roller and accordingly tends to prevent volatilization of the ink.

With the above and other objects in view that will become apparent as the nature of the inventin is better understood, reference is made to the following detailed description and accompanyingdrawings, in which:

FIGURE 1 shows a perspective view of the herein described ink reservoir, 7

, FIGURE 2 shows a cross-sectional view taken on line 2-Z of 1,

FIGURE 3 shows a top plan view of the ink reservoir,

FIGURE 4 is a detail sectional view taken along lines 4-4 of FIGURE 3,

FIGURE 5 is a perspective view of the ink pot and its base, 1

FIGURE 6 is a perspective view of the smoothing bar and its carrier, and

FIGURE 7 is a cross-section taken along lines 7--7 of FIGURE 2 and showing the smoothing bar in relation to the roller.

Referring now with greater particularity to the drawings, there is shown in FIGURE '1 a frame 23 carrying a trough-like ink container or pot 13 having end wall portions 1311.: One long edge of pot 13 is comprised of doctor blade 14, a sharp, knife-edge lip of hardened steel. Juxtaposed this doctor blade 14 is the peripheral surface of a steel inking roll 11 having a length somewhat shorter than pot 13 (see FIGURE 3) and rotatably carried by frame 23. Adjacent each end wall 13a and sealingly engaging blade 14 at each end thereof is a felt gasket 16 which act as ink seals. Though felt is the material employed in the preferred embodiment, it is of course to be understood that any suitable substitute may be employed so long as it retains the necessary characteristics, i.e. some degree of resiliency, relatively non-absorbent, and which generates a minimum of friction while in contact with moving members. Inking roll 11 rotatably journaled in conventional bearings 12 is snugly interposed between and in sealing contact with felt gaskets 10.

Pot 13 is securely fastened to a carrier base 24 adapted to be slidably engaged into channels 24a of frame 23.

Intersecting each channel 24a-through its upper surface thereof is a threaded hole 25 (see FIGURE 4) adapted to receive adjusting screw 26, whereby when carrier 24 is positioned in channels 24a, screw 26 may be advanced until the end thereof comes into abutting engagement against the inclined surface of recess 21. Further advancing of screw 26, will move carrier 24 and the rigidly attached pot 13 along channel l i a toward roll 11. Springs 27 interposed between the foward ends of carrier 24 and the terminal end of channel 24a provide sufficient resilient resistance which adjusting screws 26 overcome to properly position pot 13 with respect to ink roll 11. Positioned beneath pot 13 and juxtaposed the peripheral surface of roll 11 is a rigidly held non-rotatable cylindrical smoothing bar 16 having a length somewhat less than that of ink roller 11 (see FIGURE 7). Smoothing bar 16 is mounted on carrier 17 and held in non-rotatable position by means of locking screws 18. Carrier 17 is adapted to slidably engage channels 17a in frame 23 as shown in FIGURE 4. Threaded holes 19 intersect each of channels 17a at the upper surface thereof and are each adapted to receive a screw 26. In order to have as little area contact between roll 11 and bar 16 as possible, bar 16 has a diameter substantially less than that of roll 11.

Inclined abutrnents 28 are provided in carrier 17 whereby when said carrier is positioned in channel 17a,

and beveled ends 20a of screws 20 are advanced into engagement with carrier abutments 28, this will move carrier 23, and its associated smoothing bar 16 toward ink roll 11. Springs 29 are interposed between the forward ends of carrier 17 and frame 23 thereby providing for necessary tension control for positioning bar 15, with respect to ink roll 11.

In operation, the ink reservoir described will function as follows: doctor blade 14, along with its associated pot 13, is moved into touching engagement with ink roller 11. Pot 13 is filled with ink 9 to a height substantially above the uppermost level of blade 14. Since pot 13 is adapted for horizontal traversing, the distance between blade 14 and the peripheral surface of ink roller 11 may be set for whatever initial ink film thickness is required. As ink roll 11 revolves in a clockwise direction at 30 to 300 r.m.p., a layer of ink will be deposited thereon and doctored to an initial thickness by blade 14 by a shearing action.

As roller 11 continues to rotate in a clockwise direc- 7 11 than the aforementioned blade 14 and irons out the initial ink film to one of desired thickness which is smooth and uniform throughout the surface. of roll 11.

'By' adjusting screws 2%, the position of smoothing bar 16 relative to roll 11 can thus be controlled thereby, in turn, affording thickness control of the ink film;

I It is important that the relationship of bar 16 being closer to roll 11 than blade 14 be established or the smoothing bar will not perform correctlyv There must always be a slight excess of ink delivered to the smoothing bar by blade 14 as the smoothing bar functions to fill the hollows by moving ink from the higher levels into the adjacent lower levels. The maintenance of the slight excess is toprovide a practical margin of safety. The correct amount will become apparent to the operator of this device as it will result in a very small head or ring of ink built up near the outermost ends of the ink roll. This indicates that the excess of ink is being carried away as required.

Because of the contact pressures from blade 14 and smoothing bar 16 against the surface of ink roll 11, large quantities of frictional heat are generated which create undesirable environmental temperature conditions. Because of the volatile nature of the inks employed in this type of printing equipment, presence of elevated temperatures increases the rate at which the volatile ingredients in the ink evaporate. Accordingly, in order to lower these temperature levels and thereby minimize volatilization, this invention contemplates using the viscous ink mass 9 in pot 13 as a heatsink for dissipating this frictionally generated heat. It was initially observed that as ink roll 11 rotated in a clockwise direction, this rotation tended to induce a small but Well defined. counter-clockwise circulation of ink immediately adjacent lip 14. On further investigation it was discovered that by severely recessing pct 13 into the concave shape depicted by the drawings and locating blade 14 in an elevated but tangential position relative to the sides of such recess, the local circulation at blade edge 14 was induced to disperse and expand itself so as. to circulate along the entire inner surface of pot 13 thereby dissipating frictionally generated heat into the viscous ink mass. In order to achieve this condition however, the recessed side adjacent blade 14 must have a slope of greater than degrees. This complete circulation is depicted by arrow A in FIGURE 2. This heat sink function accordingly maintains the operative temperature of the inked surfaces at a much lower level than was otherwise possible, thereby substantially eliminating ink evaporation due to frictionally generated heat.

Thus it may now' be seen that as a result of the aforesaid novel smoothing bar concept and the further providing of a new ink pot configuration, a heat sink for reducing frictionally generated heat, this invention accomplishes the hereinbefore set forth objects in an economical and effective manner.

Having thus described a preferred embodiment of the invention, it is to be understood that various other em bodiments and modifications may be made therein without departing from the spirit of this invention or the scope of the appended claims.

I claim:

1. An improved ink reservoir comprising a rigid frame member, a rotatably journaled steel inking roll carried by said frame, a first and second pair of opposed grooves in said frame, an ink pot slidably carried by said first pair of grooves and traversable into and out of engagement with said inking roll by a pair of adjusting means; a rigidly held non-rotatable smoothing bar carried in said second pair of grooves, and movable into and out of engagement with the peripheral surface of said inking roll by another pair of adjusting means; and a doctor blade, comprising one side of the aforesaid ink pot.

2. A new and improved ink reservoir comprising: a support frame, an inking roll rotatably journaled on said frame, ink supply means carried by said frame and linearly disposed adjacent the circumferential surface of said roll, doctor blade means carried by said ink supply means and extending the length thereof and in spaced apart relation to said roll, a rigid non-rotatable means in tangential contacting relation to said roll and extending linearly thereon, said last named means being carried by the afore said frame, a first adjusting means for horizontally traversing said ink supply means into and out of engagement with said inking roll, and a second adjusting means for adjustably traversing said non-rotatable means with respect to said ink roll.

3. An improved ink reservoir comprising: a frame member, a first and second pair of opposed grooves in said frame member, an ink container means slidably carried by the frame in said first pair of grooves, a smoothing bar means slidably carried by the frame in the second pair of grooves, an inking roll rotatably journaled in said frame, the peripheral surface of said roll being in tangential contact with each of the aforesaid ink container and smoothing bar means, wherein the portion of said ink container means in tangential contact With the inking roll is comprised of a precision ground doctor blade, said blade having a length of longer extent than the inking roll, and gasket means interposed at each end of said blade in sealing engagement with said inking roll.

4. An improved ink reservoir comprising: a frame member, a first and second pair of opposed grooves in said frame member, an ink container means slidably carried by the frame in said first pair of grooves, a smoothing bar means slidably carried by the frame in the second pair of grooves, an inking roll rotatably journaled" in said frame, the peripheral surface of said roll being in tangential contact with each of the aforesaid ink container and smoothing bar means, wherein the portion of said ink container means in tangential contact with the inking roll is comprised of a precision ground doctor blade, said blade having a length of longer extent than the inking roll, gasket means interposed at each end of said blade in sealing engagement with said inking roll, and wherein the aforementioned smoothing bar is non-rotatable and of a size substantially smaller than the ink roll against which it acts.

References Cited by the Examiner UNITED STATES PATENTS 694,749 3/02 Hobbs 118-261 842,283 1/07 West 118-261 890,162 6/08 Munz 101154 1,293,305 2/19 Bechman 101350 2 1,825,999 10/31 Fankboner 101365 1,995,701 3/35 But-tner l01350 2,001,890 5/35 Rix 101-364 X 2,449,909 9/48 Putnam et a1. 101364 3,040,442 6/62 Overton l01169 X EUGENE R. CAPOZIO, Primary Examiner.

ROBERT E. PULFREY, Examiner. 

1. AN IMPROVED INK RESERVOIR COMPRISING A RIGID FRAME MEMBER, A ROTATABLY JOURNALED STEEL INKING ROLL CARRIED BY SAID FRAME, A FIRST AND SECOND PAIR OF OPPOSED GROOVES IN SAID FRAME, AN INK POT SLIDABLY CARRIED BY SAID FIRST PAIR OF GROOVES AND TRAVERSABLE INTO AND OUT OF ENGAGEMENT WITH SAID INKING ROLL BY A PAIR OF ADJUSTING MEANS; A RIGIDLY HELD NON-ROTATABLE SMOOTHING BAR CARRIED IN SAID SECOND PAIR OF GROOVES, AND MOVABLE INTO AND OUT OF ENGAGEMENT WITH THE PERIPHERAL SURFACE OF SAID INKING ROLL BY ANOTHER PAIR OF ADJUSTING MEANS; AND A DOCTOR BLADE, COMPRISING ONE SIDE OF THE AFORESAID INK POT. 